Space Travel

NASA Says Mars Appears to Have Flowing Water

In a press conference on Monday, NASA announced a huge discovery for Mars fans: evidence of flowing water, which drastically increases the chance of human habitation on the red planet and raises the question of whether life previously existed there.

According to NASA, the Mars Reconnaissance Orbiter (M.R.O.) noticed dark streaks on the surface of Mars that grew and shrank during the changing of seasons, and further investigation confirmed that they appeared to be caused by flowing “briny” water. While water ice has already been found near the polar caps of Mars, liquid water would not be able to flow on the planet’s surface due to its freezing temperatures, but briny water—essentially salt hydrated with water molecules—would be able to retain its liquid form despite those temperatures. Whether water exists underground stored in aquifers remains to be seen.

The existence of liquid water on Mars has massive implications for future space travel, notably that it would be easier for humans to travel there—not just for drinking, but also for creating oxygen and, possibly, rocket fuel.

Prior to the announcement, NASA’s inclusion of three academics on the panel prompted speculation that they'd found flowing water: Alfred McEwen, Lujendra Ojha, and Mary Beth Wilhelm, who will submit a paper to the European Planetary Science Congress this week detailing their discovery that briny water flows seasonally on Mars. (Ojha was the first to notice dark streaks on the surface of Mars that changed size over time, leading him to hypothesize that these “recurring slope lines” were caused by briny water.)

Several previous discoveries indicate that water once covered Mars, with NASA announcing back in March that the planet recently (in planetary terms, that’s 4.5 billion years ago) had an ocean larger than Earth’s own Arctic Ocean. (Eighty-seven percent of that water was lost to space. Yes, water can just up and leave a planet. Isn’t space fascinating, and also terrifying?)